Free Protect PDF Tool
This free tool adds a password to a PDF using 256-bit AES encryption, so only people who know the password can open it. You can also block printing, copying text or editing. The password is used once to lock your file and is not saved. If you forget it, the file cannot be opened again, so store it safely.
Protect PDF
PDF Tools
About this tool
Contracts, payslips, ID scans and price lists often travel by email or messaging apps, where a stray forward is easy. A password on the PDF means the content stays unreadable to anyone who gets the file without the password, whatever happens to the message that carried it.
The tool encrypts the file with qpdf using AES-256, the strongest standard encryption defined for PDF. The open password is what a reader types to view the file. The optional owner password controls the permissions; if you leave it empty, it is set to the same value as the open password. Permission limits such as no printing or no copying are honoured by most viewers but are weaker than the open password itself.
Send the password by a different channel than the file, for example a phone call or a separate message. Use at least eight characters and avoid obvious words. We cannot recover a lost password, because we never keep it. Upload up to 20 MB. If the file already has a password, remove it first with the Unlock PDF tool.
Frequently asked questions
How strong is the protection?
The file is encrypted with 256-bit AES, the strongest encryption in the PDF standard. A long, unusual password is what makes it hard to guess, so use at least eight characters and avoid names or dates.
What is the difference between the open and owner password?
The open password is needed to view the file. The owner password controls permissions like printing and copying. If you leave the owner password empty, the open password is used for both. Permission limits depend on the viewer respecting them.
What if I forget the password?
It cannot be recovered. We do not store passwords or keep copies of your file, and the encryption cannot be reversed without the password. Keep the password in a password manager and keep your original unprotected file somewhere safe.
Do you see or store my password?
The password is sent to our server over your connection, used once to lock the file and then discarded with the temporary files. It is not written to logs or kept. Use the tool over a secure connection and never reuse an important password.
Can I protect a PDF that already has a password?
Not directly. Remove the existing password with the Unlock PDF tool, then protect the unlocked copy with a new password.